CD Key Issues

[Truce]

I have an actual hard copy of this game, and seeing as it's a product of Sierra Games, figured I could activate it on Steam with the CD-Key so I could have access to a digital copy and do away with the old discs. Unfortunately, as many times as I tried, it would not accept the CD Key on the disc sleeve. Any thoughts on why this is?

[Decimatarius]

I just tried mine now and no luck sadly.

[devanmedrow]

I have a disc. And would like to change it to steam version.